1. Cell Cycle

2. Cell Theory: * All living things composed of cells * Cells are the basic units of structure and function in living things. * New cells are produced from existing cells

3. Nucleus of the Cell: Controls most cell processes and contains the hereditary information. This is found as Deoxyribonucleic Acid (DNA) Chromatin: DNA bound to protein – granular and visible in the nucleus. Chromosomes: Chromatin that condenses in preparation for cell division. DNA: Coded instructions for making proteins.

4. Microtubules: They aide in cell division, separating chromosomes (known as c entrioles in animal cells).

5. PROKARYOTE CELL DIVISION EUKARYOTE CELL DIVISION Asexual Reproduction Growth and replacement of old and/or dying cells DNA = One Circular Chromosome and Plasmids DNA = 10-50 chromosomes per cell Humans = 46 (23 identical pairs) Cell Division called the Cell CycleCell Division called Binary Fission

6. Cell Cycle: Phase 1: Interphase Phase 2: Mitosis Phase 3: Cytokinesis G 1 - primary growth phase S – synthesis; DNA replicated G 2 - secondary growth phase

7. Phase 1: Interphase G 1 - primary growth phase S – synthesis; DNA replicated G 2 - secondary growth phase Cell Matures: Growth and Organelles DNA copied/replicated Cell Structures needed for division madeCentrioles

8.  Chromatin condenses into chromosomes  Mitotic spindle forms and attaches to centromeres  Nuclear membrane/nucleolus broken down.

9. dissolving Centrioles

10.  Chromosomes line up at the equator of the cell

11. Centriole CentromereEquator

12.  Sister Chromatids pulled apart to opposite poles of the cell.

13. Equator

15.  Sister Chromatids completely at opposite poles  Nuclear envelope forms  Nucleolus appears  Cytokinesis occurs

16. Equator

17. Phase 3: Cytokinesis Division of cell into two – Division of the cytoplasm by a cleavage furrow Cleavage Furrow

18. 18 XXXXXXXXXX ******************* XXXXXXX ************ XXXXXXXXXXX ******************XXXXXXX

19. 19 XXXXXXXXX ************** XXXXXXXX ************ XXXXXXXXXXXXXXXX ***************************

20. 20 Interphase Early prophase Mid-Prophase Late Prophase Metaphase Late Anaphase Early Anaphase Early Telophase, Begin cytokinesis Late telophase, Advanced cytokinesis

21.  http://www.youtube. com/watch?v=ZEwdd r9ho- 4&feature=related http://www.youtube. com/watch?v=ZEwdd r9ho- 4&feature=related

22. 22 Karyotype A picture of the chromosomes from a human cell arranged in pairs by size First 22 pairs are called autosomes Last pair are the sex chromosomes XX female or XY male

23. 23 Y - Chromosome X - Chromosome The Y Chromosome Decides

24. (Eggs and Sperm) Spermatogenesis (formation of sperm) Females: Males: Oogenesis (formation of eggs) Two Stages: Meiosis I and Meiosis II During Meiosis I – Homologs form Tetrads and crossing over occurs, all resulting cells are still diploid (2N) 46 chromosomes During Meiosis II – Chromosomes are split and all cells become haploid (1N) 23 chromosomes Why is this important? Entire process called reduction division

25. 25 Homologous chromosomes (compare to sister chromatids) Homologous chromosomes (compare to sister chromatids) Join to form a tetrad Called Synapsis (compare to a centromere)

26. 26 Homologous chromosomes in a tetrad cross over each other Homologous chromosomes in a tetrad cross over each other Pieces of chromosomes or genes are exchanged Pieces of chromosomes or genes are exchanged Produces Genetic recombination in the offspring Produces Genetic recombination in the offspring

27. 27 Crossing-over multiplies the already huge number of different gamete types

28. Lets compare Mitosis and Meiosis – What do you know?

29. 46 chromatids (92 chromosomes, paired after replication – held by a synapsis/centro mere) 46 chromosomes each side Mitosis: 46 chromosomes Meiosis: 23 chromosomes

30. 30MitosisMeiosis Number of divisions 12 Number of daughter cells 24 Genetically identical? YesNo Chromosome # Same as parent Half of parent Where Somatic cells Germ cells When Throughout life At sexual maturity Role Growth and repair Sexual reproduction